Any electrical system that includes systems that have different ground references or that have the capability to produce current surges is required to incorporate galvanic isolation to protect both the system and the user.
There are a number of solutions available that offer galvanic isolation between two electrical systems. One such solution is a multi-die approach that includes a transformer connected between the two systems. Data are transferred across the transformer via magnetic fields by utilizing the first system to apply short pulses on one side; these pulses are transmitted across the transformer and the data are decoded on the other side by the second system. Another solution is similar to that just described, but uses a capacitor to isolate two electrical systems instead of a transformer. Yet another solution utilizes optical coupling whereby a light emitting diode (LED) in a first system emits light and a photodiode in the second system detects the light and generates electrical current; the LED and photodiode are typically built from III-V or II-VI semiconductor materials such as GaAs and InGaAs, with the LED and the photodiode being physically distinct units.
Currently available galvanic isolation solutions require multiple individual semiconductor die that are connected by wire bonds and are relatively slow. There is a need for a high speed galvanic isolation system that allows for the integration of all of the system elements onto a single semiconductor substrate.